Chick-fil-A emailed customers this week expressing excitement about National Sandwich Day.
However, this year's National Sandwich Day falls on a Sunday — when all Chick-fil-A locations are closed.
Popeyes is relaunching its chicken sandwich this Sunday, on National Sandwich Day.
This year, National Sandwich Day is on a Sunday — which means Chick-fil-A can't celebrate the day.
This week, some Chick-fil-A customers got emails from the chain about celebrating National Sandwich Day. The annual celebration takes place on November 3, which falls on a Sunday this year.
Chick-fil-A is famously closed on Sundays. So, on Thursday, the chicken chain emailed customers to apologize for their mistake.
"We recently sent an email that included a message about National Sandwich Day, which naturally we were very excited about," the email reads. "We didn't realize it falls on Sunday when we are closed. We apologize for the confusion and hope to see you soon (Monday-Saturday)."
This year, Popeyes is using National Sandwich Day as an opportunity to relaunch its chicken sandwich. The chain took a jab at Chick-fil-A in a video announcing the return of the popular sandwich, showing a man adding the text "Open Sunday" to a Popeyes sign.
"To be honest, it was a mere coincidence that this year's National Sandwich Day happens to be on a Sunday," Bruno Cardinali, Popeyes' head of marketing for North America, told Business Insider.
Chick-fil-A is never open on Sundays, in keeping with the Christian faith of the chain's founder and his family.
"Closing our business on Sunday, the Lord's Day, is our way of honoring God and showing our loyalty to Him," Chick-fil-A founder Truett Cathy wrote in his book "Eat Mor Chikin: Inspire More People."
Cathy continued: "My brother Ben and I closed our first restaurant on the first Sunday after we opened in 1946, and my children have committed to closing our restaurants on Sundays long after I'm gone. I believe God honors our decision and sets before us unexpected opportunities to do greater work for Him because of our loyalty."
Graham Rapier contributed reporting to this article.